1. Field of the Invention:
This invention relates to filling hole valves for sandblasters, and more particularly to an air jet actuated swing valve and hinge mechanism operative to automatically close the filling hole of a sandblaster and holding tank upon air pressure being applied to the tank.
2. Description of the Prior Art:
U.S. Pat. Nos. 1,309,671; 3,115,369; 3,253,866 and 4,118,075 all show the use of swing type valves for admitting granular materials into a chamber to be pressurized for conveyance through the bottom of the tank in an air-flow conduit. None of these four patents is directed specifically to use in sandblasting. U.S. Pat. Nos. 979,897 and 699,405 describe sandblasting equipment having pivotally hinged hopper valves that are manually operated for closure prior to pressurizing the associated sand holding tank.
It is the principal object of this invention to provide a novel and improved automatic swing valve for sandblasters facilitating filling of the delivery tank by gravity feed from the sand supply hopper.
A more particular object is to provide a pressurized air jet acuated swing valve that is so hinged with respect to the underside of the sand delivery opening within the top head of the sand delivery tank as to fit squarely against the opening seat in the tank head wall whenever the swing value is maintained in closed position due to air pressure within the delivery tank.
Yet another object of the invention is to provide a filling hole valve of the character described wherein the swing valve body is in the form of a round plate having an annular gasket seated in a peripheral recess in the upper surface of the plate, the plate being adapted to seat and seal against a substantially coaxial, circular sand filling opening between the supply head and its associated sand delivery tank, and the sand filling opening being of sufficient size to permit manual removal and replacement of the gasket therethrough when the sand delivery tank is depressurized.
Still another object of the invention is to provide a sandblaster swing-valve mechanism of the character described wherein the hinge shaft of the swing valve body is loosely journalled in a pair of opposed, vertically-slotted openings in brackets supported by the underside of the tank head sand filling opening to provide for free swinging of the valve body with respect to the inside of the tank when in its open position, while at the same time providing for self-adjustment seating against the tank head sand opening whenever the swing valve is moved into closed or seated position upon pressurizing the sand delivery tank prior to a sandblasting operation.
Still another object is to provide an automatic swing valve for sandblasters which is superior to such swing valves heretofore devised, which will be comparatively simple and economical in construction, and dependable and long-wearing in operation.
Other objects, features and advantages of the invention will be apparent from the following description when read with reference to the accompanying drawings.